Amazon Elastic Block Store (Amazon EBS)

Amazon Elastic Block Store (Amazon EBS) provides block level storage volumes for use
with EC2 instances. EBS
volumes are highly available and reliable storage volumes that can be attached to
any running
instance that is in the same Availability Zone. EBS volumes that are attached to an
EC2 instance
are exposed as storage volumes that persist independently from the life of the instance.
With
Amazon EBS, you pay only for what you use. For more information about Amazon EBS pricing,
see the
Projecting Costs section of the Amazon Elastic Block Store page.

Amazon EBS is recommended when data must be quickly accessible and requires long-term
persistence. EBS volumes are particularly well-suited for use as the primary storage
for file
systems, databases, or for any applications that require fine granular updates and
access to
raw, unformatted, block-level storage. Amazon EBS is well suited to both database-style
applications
that rely on random reads and writes, and to throughput-intensive applications that
perform
long, continuous reads and writes.

For simplified data encryption, you can launch your EBS volumes as encrypted volumes.
Amazon EBS encryption offers you a simple encryption solution for your EBS volumes
without the need for
you to build, manage, and secure your own key management infrastructure. When you
create an
encrypted EBS volume and attach it to a supported instance type, data stored at rest
on the
volume, disk I/O, and snapshots created from the volume are all encrypted. The encryption
occurs
on the servers that hosts EC2 instances, providing encryption of data-in-transit from
EC2
instances to EBS storage. For more information, see Amazon EBS Encryption.

Amazon EBS encryption uses AWS Key Management Service (AWS KMS) master keys when
creating encrypted volumes and any
snapshots created from your encrypted volumes. The first time you create an encrypted
EBS volume
in a region, a default master key is created for you automatically. This key is used
for
Amazon EBS encryption unless you select a Customer Master Key (CMK) that you created
separately using the
AWS Key Management Service. Creating your own CMK gives you more flexibility, including
the ability to create,
rotate, disable, define access controls, and audit the encryption keys used to protect
your
data. For more information, see the AWS Key Management Service Developer Guide.

You can attach multiple volumes to the same instance within the limits specified by
your AWS
account. Your account has a limit on the number of EBS volumes that you can use, and
the total
storage available to you. For more information about these limits, and how to request
an
increase in your limits, see Request to Increase the Amazon EBS Volume
Limit.

Features of Amazon EBS

You can create EBS General Purpose SSD (gp2), Provisioned IOPS SSD (io1), Throughput Optimized HDD (st1), and
Cold HDD (sc1) volumes up to 16 TiB in size. You can mount these volumes as devices on
your Amazon EC2 instances. You can mount multiple volumes on the same instance, but
each volume
can be attached to only one instance at a time. You can dynamically change the
configuration of a volume attached to an instance. For more information, see Creating an Amazon EBS Volume.

With General Purpose SSD (gp2) volumes, you can expect base performance of 3 IOPS/GiB, with the
ability to burst to 3,000 IOPS for extended periods of time. Gp2 volumes are
ideal for a broad range of use cases such as boot volumes, small and medium-size
databases, and development and test environments. Gp2 volumes support up to
10,000 IOPS and 160 MB/s of throughput. For more information, see General Purpose SSD (gp2) Volumes.

With Provisioned IOPS SSD (io1) volumes, you can provision a specific level of I/O performance.
Io1 volumes support up to 20,000 IOPS and 320 MB/s of throughput. This
allows you to predictably scale to tens of thousands of IOPS per EC2 instance. For
more
information, see Provisioned IOPS SSD (io1) Volumes.

Throughput Optimized HDD (st1) volumes provide low-cost magnetic storage that defines
performance in terms of throughput rather than IOPS. With throughput of up to 500
MiB/s,
this volume type is a good fit for large, sequential workloads such as Amazon EMR,
ETL, data
warehouses, and log processing. For more information, see Throughput Optimized HDD (st1) Volumes.

Cold HDD (sc1) volumes provide low-cost magnetic storage that defines performance in
terms of throughput rather than IOPS. With throughput of up to 250 MiB/s, sc1 is a good
fit ideal for large, sequential, cold-data workloads. If you require infrequent access
to
your data and are looking to save costs, sc1 provides inexpensive block storage. For
more information, see Cold HDD (sc1) Volumes.

EBS volumes behave like raw, unformatted block devices. You can create a file system
on top of these volumes, or use them in any other way you would use a block device
(like a
hard drive). For more information on creating file systems and mounting volumes, see
Making an Amazon EBS Volume Available for Use.

You can use encrypted EBS volumes to meet a wide range of data-at-rest encryption
requirements for regulated/audited data and applications. For more information, see
Amazon EBS Encryption.

You can create point-in-time snapshots of EBS volumes, which are persisted to Amazon
S3.
Snapshots protect data for long-term durability, and they can be used as the starting
point for new EBS volumes. The same snapshot can be used to instantiate as many volumes
as
you wish. These snapshots can be copied across AWS regions. For more information,
see
Amazon EBS Snapshots.

EBS volumes are created in a specific Availability Zone, and can then be attached
to
any instances in that same Availability Zone. To make a volume available outside of
the
Availability Zone, you can create a snapshot and restore that snapshot to a new volume
anywhere in that region. You can copy snapshots to other regions and then restore
them to
new volumes there, making it easier to leverage multiple AWS regions for geographical
expansion, data center migration, and disaster recovery. For more information, see
Creating an Amazon EBS Snapshot, Restoring an Amazon EBS Volume from a Snapshot, and Copying an Amazon EBS Snapshot.

A large repository of public data set snapshots can be restored to EBS volumes and
seamlessly integrated into AWS cloud-based applications. For more information, see
Using Public Data Sets.

Performance metrics, such as bandwidth, throughput, latency, and average queue length,
are available through the AWS Management Console. These metrics, provided by Amazon
CloudWatch, allow you to
monitor the performance of your volumes to make sure that you are providing enough
performance for your applications without paying for resources you don't need. For
more
information, see Amazon EBS Volume Performance on Linux Instances.